I'm a little worried at that size, myself. As a very casual user of OpenOffice, the only deficiency I've experienced in the last couple years is that it takes a long time to start up - the first time; once it's in memory, it's fine. Since 90% of the point is displaying text, it sounds like there's going to be an new mandatory megabyte or so to page in. We'll see.
My real worries about OpenOffice are outside the control of the OpenOffice authors. I'd like to see the anti-trust judge fine Microsoft $50 billion for that obscenity of a standards proposal on their new format, and another $50 billion for deliberately using an incompatible ODF implementation.
Just enough to remind Microsoft what "abuse of monopoly" means. Not that it would ever happen.
I'm not comforted by the seemingly slow adoption of the new Microsoft formats; it takes a long time for companies to switch, but switch they do: I'm starting to see the dread ...x formats at work in just the last couple months.